CN1697104A - Electrical contact material containing organic heterojunction and device thereof - Google Patents

Abstract

Located between organic semiconductor and metal electrode and containing hetero junction, the electric contact material is composed of organic semiconductors in electron type and in cavity type as well as hetero junction built from organic semiconductors in electron type and in cavity type. The invention also is related to organic diode, organic field effect transistor and organic photovoltaic device, which use the electric contact material of containing organic hetero junction as buffer layer.

Description

Electrical contact material containing organic heterojunction and device thereof

technical field

The invention relates to an electrical contact material using an organic heterojunction (organic heterojunction) to realize effective contact between a metal electrode and an organic semiconductor. The invention also relates to an organic field effect transistor device and an organic photovoltaic device using an electrical contact material containing an organic heterojunction as a buffer layer.

Background technique

In recent years, the research on organic semiconductor materials has been extremely active, showing broad application prospects in information display and photovoltaic cells. Chinese patent 02129458.5 discloses a sandwich-type organic field effect transistor, which provides a method of using two or more organic semiconductor materials to form a new type of semiconductor. This method can effectively improve the overall performance of organic field effect transistors, especially can effectively lower the threshold voltage. Chinese patent 03102064.x discloses a method of realizing a bipolar organic field effect transistor by using an organic semiconductor heterojunction, and a method of realizing a normally-on field effect transistor by utilizing the conductive properties of the organic semiconductor heterojunction. In Chemical Physics Letters (Chemical Physics Letters), Vol. 407, page 87, 2005, Wang Jun et al. reported that the organic heterojunction interface has high conductivity, and used the organic heterojunction to realize the normally open and bipolar field effect transistor. Therefore, the organic semiconductor device using two organic semiconductor composites as the active layer exhibits different device performance from that of a single material. Chinese patent 200410010768.3 discloses a method of using a non-reactive buffer layer to achieve effective contact between metal electrodes and semiconductors. This method uses high-conductivity materials as the buffer layer of the device to increase the carrier in the organic field effect transistor. injection efficiency.

Contents of the invention

One of the objects of the present invention is to provide an electrical contact material comprising an organic heterojunction;

Another object of the present invention is to provide an organic field effect transistor device using an electrical contact material containing an organic heterojunction as a buffer layer;

The third object of the present invention is to provide an organic photovoltaic device using an electrical contact material containing an organic heterojunction as a buffer layer.

The invention utilizes the high conductivity of the interface of the heterojunction of the organic semiconductor, and overcomes the limitations of the dipole action and energy level mismatch on the interface of the metal and the organic semiconductor to charge injection and derivation. The high conductivity of the organic semiconductor heterojunction interface comes from the interface dipole generated after the contact of the organic semiconductor. This interface dipole will form a strong dipole electric field, which induces carriers to accumulate at the interface, resulting in the formation of regions of high conductance. This high-conductivity region effectively reduces the charge injection barrier and enhances the tunneling probability of charges from the metal electrode to the organic semiconductor. Therefore, the use of organic semiconductor heterojunctions as electrical contact materials can significantly improve the charge injection and derivation properties.

The present invention uses an organic heterojunction composed of two or more organic semiconductor materials as an electrical contact material, and uses this electrical contact material containing an organic heterojunction as a buffer in an organic field effect transistor device and an organic photovoltaic device The layer realizes effective contact between the metal electrode and the organic semiconductor.

Electrical contact materials containing organic heterojunctions are composed of electronic and hole organic semiconductors and their heterojunctions. The hole-type semiconductor layers here are made of copper phthalocyanine, nickel phthalocyanine, zinc phthalocyanine, cobalt phthalocyanine, platinum phthalocyanine, free phthalocyanine, tetrathiophene, pentathiophene, hexathiophene, bis(biphenyl- 4,4')-2,2'-dithiophene or at least two materials, the electronic semiconductor layer is respectively made of fluorophthalocyanine copper, fluorophthalocyanine zinc, fluorophthalocyanine iron, fluorophthalocyanine One or at least two materials of cobalt and fluorinated hexathiophene. The electrical contact materials containing organic heterojunctions are all prepared by vacuum molecular vapor deposition method, and the overall thickness is zero to fifty nanometers.

Using an electrical contact material containing an organic heterojunction as a buffer layer can effectively improve the contact effect between the metal electrode and the organic semiconductor. Metal electrodes are characterized by a work function greater than 4.3 eV and less than 5.7 eV, including indium tin oxide (ITO), magnesium (Mg), aluminum (Al), silver (Ag), tantalum (Ta), chromium (Cr), One of molybdenum (Mo), copper (Cu), gold (Au) and platinum (Pt) or a metal alloy of two or more of them. The contact resistance of the transistor using the electrical contact material containing the organic heterojunction as the buffer layer is significantly reduced, thereby enhancing the charge injection efficiency, and the device performance of the transistor is obviously improved. An organic photovoltaic device using an electrical contact material containing an organic heterojunction as a buffer layer realizes the effective derivation of charges, and the performance of the device is greatly improved.

Description of drawings

Fig. 1a is a schematic diagram of a diode structure using an electrical contact material containing an organic heterojunction as a buffer layer according to the present invention. Wherein, 1 is a substrate, 2 and 5 are electrodes, 3 is an organic semiconductor active layer, and 4 is a buffer layer composed of an electrical contact material containing an organic heterojunction.

Figure 1b is a schematic diagram of a diode structure without a buffer layer. Wherein, 1 is a substrate, 2 and 4 are electrodes, and 3 is an organic semiconductor active layer.

Fig. 1c is the electric current-voltage curve under dark state (curve (b)) and illumination (curve (c)) condition of the diode structure that contains the electric contact material that contains organic heterojunction as buffer layer in embodiment 1 of the present invention, and Current-voltage curves of the diode structure without buffer layer in the dark state (curve (a)).

Fig. 2a is a schematic diagram of the device structure of an organic field effect transistor using an electrical contact material containing an organic heterojunction as a buffer layer. Wherein, 1 is a substrate, 2 is a gate electrode, 3 is an insulating layer, 4 is an organic semiconductor active layer, and 5 is a buffer layer composed of an electrical contact material containing an organic heterojunction. 6 is a source/drain electrode. Figure 2a is also a drawing of the abstract of the specification.

Fig. 2b is an output characteristic curve of Embodiment 2 of the present invention.

Fig. 2c is the transfer characteristic curve of Example 2 of the present invention.

Fig. 3a is a schematic diagram of the structure of an organic photovoltaic device using an electrical contact material containing an organic heterojunction as a buffer layer. Wherein, 1 is a substrate, 2 and 6 are electrodes, 3 is a buffer layer composed of an electrical contact material containing an organic heterojunction, and 4 and 5 are organic semiconductor active layers.

Fig. 3 b is the organic photovoltaic device without buffer layer in the embodiment 3 of the present invention in dark state (curve (a)) and under light (curve (b)) and the organic photovoltaic device containing buffer layer in dark state (curve (c) ) and the current-voltage curves under light (curve (d)).

Detailed ways

Describe the present invention below in conjunction with accompanying drawing.

Figure 1a is a schematic diagram of a diode structure using an electrical contact material containing an organic heterojunction as a buffer layer. A conductive material is arranged on the substrate 1 to form an electrode 2, a hole-type and (or) electron-type semiconductor material is arranged on the electrode 2 to form an organic active layer 3, and a hole-type and (or) electron-type semiconductor material is arranged on the organic active layer An electrical contact material containing an organic heterojunction is formed on the buffer layer 4 to form a buffer layer 4, and the electrode 5 is arranged on the buffer layer 4.

Fig. 2a is a schematic diagram of the device structure of an organic field effect transistor using an electrical contact material containing an organic heterojunction as a buffer layer. The conductive material layer is arranged on the substrate 1 to form the gate electrode 2, the insulating material is arranged on the gate electrode 2 to form the insulating layer 3, and the electronic type and (or) hole type semiconductor material is arranged on the insulating layer 3 to form the active layer of the semiconductor layer 4. Hole-type and (or) electron-type semiconductor materials are arranged on the semiconductor active layer 4 to form an electrical contact material containing an organic heterojunction to form a buffer layer 5 , and the source and drain electrodes 6 are arranged on the buffer layer 5 .

Fig. 3a is a schematic diagram of the structure of an organic photovoltaic device using an electrical contact material containing an organic heterojunction as a buffer layer. A conductive material is placed on the substrate 1 to form an electrode 2, a hole-type and (or) electron-type semiconductor material is placed on the electrode 2 to form an electrical contact material containing an organic heterojunction, and a buffer layer 3 is formed, and the semiconductor active layer 4 is placed on the On the buffer layer 3 , a semiconductor active layer 5 is disposed on the semiconductor active layer 4 , and an electrode 6 is formed on the semiconductor active layer 5 .

The present invention is further described below by way of examples.

Example 1:

Copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), nickel phthalocyanine (NiPc), cobalt phthalocyanine (CoPc), free phthalocyanine (H ₂ Pc), platinum phthalocyanine (PtPc), fluorinated copper phthalocyanine (F ₁₆ CuPc), Zinc Fluorophthalocyanine (F ₁₆ ZnPc), Iron Fluorophthalocyanine (F ₁₆ FePc) and Cobalt Fluorophthalocyanine (F ₁₆ CoPc) are commercial products and used after sublimation purification. Tetrathiophene (4T), pentathiophene (5T), hexathiophene (6T), bis(biphenyl-4,4')-2,2'-dithiophene (BP2T) and fluorinated hexathiophene (DFH -6T) is a synthetic material that is used after sublimation purification. The conductive thin film indium tin oxide (ITO) is used as the electrode 2 to cover the glass substrate 1, and the whole glass containing the conductive thin film is a commercial product.

The diode structure containing the electrical contact material of the organic heterojunction as the buffer layer is shown in Fig. 1a. All organic layers are prepared by vacuum molecular vapor deposition method, and the vacuum degree is 10 ^-5 Pa. The ITO electrode on the glass substrate 1 serves as an anode and constitutes the electrode 2 . First, 40 nanometers of zinc phthalocyanine is deposited on the ITO electrode 2 by vacuum molecular vapor deposition to form an organic semiconductor active layer 3 . Then, the buffer layer 4 is formed by depositing an electrical contact material containing an organic heterojunction on the organic semiconductor active layer 3 by using a vacuum molecular vapor deposition method. The electrical contact material here is composed of electron-type and hole-type organic semiconductors and their heterojunctions. The hole-type semiconductor layers are composed of copper phthalocyanine, nickel phthalocyanine, zinc phthalocyanine, cobalt phthalocyanine, and phthalocyanine. One of platinum, free phthalocyanine, tetrathiophene (4T), pentathiophene (5T), hexathiophene (6T), bis(biphenyl-4,4')-2,2'-dithiophene (BP2T) or at least two kinds of materials, and the electronic semiconductor layer is composed of one or at least two materials of fluorophthalocyanine copper, fluorophthalocyanine zinc, fluorophthalocyanine iron, fluorophthalocyanine cobalt and fluorinated hexathiophene . The manufacturing method of the buffer layer 4 is to first deposit a type of organic semiconductor by vacuum molecular vapor deposition method, the substrate temperature is 150 degrees Celsius, and the thickness is 2 nanometers to form discrete crystal grains, and then adopt the same method as above under the same conditions Deposit another organic semiconductor with a thickness of 2 nanometers, and they together form an organic heterojunction interpenetrating network structure, constituting an electrical contact material containing an organic heterojunction as a buffer layer. Finally, different metals are deposited on the buffer layer 4 by vacuum thermal evaporation to form an electrode 5, which is used as a cathode, and the vacuum during thermal evaporation is 10 ⁻⁴ Pa.

In order to compare the improvement effect of the buffer layer on the electrical contact performance, a device without a buffer layer was fabricated, and the device structure is shown in Figure 1b. The preparation of the organic layers all adopts the vacuum molecular vapor deposition method, and the vacuum degree is 10 ^-5 Pa. The ITO electrode on the glass substrate 1 serves as an anode and constitutes the electrode 2 . First, 40 nanometers of zinc phthalocyanine is deposited on the electrode 2 by using a vacuum molecular vapor deposition method to form an organic semiconductor active layer 3 . Then, different metals are deposited on the organic semiconductor active layer 3 by vacuum thermal evaporation to form an electrode 4, which is used as a cathode, and the vacuum during thermal evaporation is 10 ⁻⁴ Pa.

Table 1 lists the conductivities of the devices with the two structures described in Fig. 1a and Fig. 1b for low work function metal electrodes. The conductivity in the table is measured at the positive 1 volt of the anode, eV stands for electron volts, and S/cm stands for Siemens per centimeter. For metal electrodes with low work function, magnesium (Mg) and aluminum (Al), devices with or without a buffer layer exhibit Schottky contacts, but compared to devices without a buffer layer, the corresponding The conductivity of the buffer layer devices has been improved.

Table 1 The buffer layer cathode Cathode work function (eV) Conductivity (S/cm) (excluding buffer layer) Conductivity (S/cm) (including buffer layer) contact characteristics ZnPc/F ₁₆ CuPc Mg 2.87 1.1×10 ^-8 2.5×10 ^-8 schottky contact ZnPc/F ₁₆ CuPc Al 4.28 0.8×10 ^-8 1.6×10 ^-8 schottky contact CuPc/F ₁₆ CuPc Al 4.28 1.0×10 ^-8 3.1×10 ^-8 schottky contact 6T/DFH-6T al 4.28 6.1×10 ^-8 1.2×10 ^-7 schottky contact 6T/CuPc/F ₁₆ CuPc al 4.28 4.4×10 ^-8 8.3×10 ^-8 schottky contact BP2T/F ₁₆ CuPc al 4.28 5.4×10 ^-8 2.1×10 ^-7 schottky contact

Table 2 lists the conductivities of the devices with the two structures described in Fig. 1a and Fig. 1b for high work function metal electrodes. For the electrode work function of 4.3eV to 5.1eV, silver (Ag), tantalum (Ta), chromium (Cr), molybdenum (Mo), copper (Cu), the conductivity of the device containing the buffer layer is higher than that without the buffer layer 2 to 3 times the device conductivity, and all exhibit ohmic transmission. For higher work function metal electrodes, gold (Au) and platinum (Pt), the electrical properties of all devices exhibited ohmic transport, and the conductivity of the device containing the buffer layer was slightly improved. Therefore, using a buffer layer composed of an electrical contact material containing an organic heterojunction can effectively improve the contact between the metal electrode and the organic semiconductor, and its scope of application is all electrode materials with a work function greater than 4.3eV and less than 5.7eV.

Table 2 The buffer layer cathode Cathode work function (eV) Conductivity (S/cm) (excluding buffer layer) Conductivity (S/cm) (including buffer layer) contact characteristics ZnPc/F ₁₆ CuPc Ag 4.26 5.2× ^10-10 1.6×10 ^-9 ohmic contact CuPc/F ₁₆ CuPc Ag 4.26 2.7×10 ^-9 3.8×10 ^-8 ohmic contact PtPc/F ₁₆ ZnPc Ag 4.26 4.1× ^10-10 1.1×10 ^-9 ohmic contact 5T/F ¹⁶ CuPc Ag 4.26 3.6× ^10-9 6.9× ^10-9 ohmic contact 4T/DFH-6T Ag 4.26 8.9×10 ^-8 7.2×10 ^-7 ohmic contact BP2T/F ₁₆ ZnPc Ag 4.26 1.3×10 ^-7 8.8×10 ^-7 ohmic contact NiPc/F ₁₆ CoPc Ag 4.26 2.1×10 ^-9 5.8×10 ^-8 ohmic contact ZnPc/CuPc/F ₁₆ CuPc Ag 4.26 4.2× ^10-9 6.9×10 ^-8 ohmic contact 4T/5T/DFH-6T Ag 4.26 9.1×10 ^-8 8.0×10 ^-7 ohmic contact CuPc/F ₁₆ CuPc/F ₁₆ ZnPc Ag 4.26 6.2× ^10-9 7.5×10 ^-8 ohmic contact ZnPc/F ₁₆ CuPc Ta 4.25 2.1×10 ^-9 6.2× ^10-9 ohmic contact CuPc/F ₁₆ FePc Ta 4.25 1.0×10 ^-9 3.1×10 ^-9 ohmic contact H ₂ Pc/F ₁₆ FePc Ta 4.25 7.0×10 ^-10 1.5×10 ^-9 ohmic contact NiPc/CuPc/ Ta 4.25 6.8× ^10-9 9.1×10 ^-9 ohmic contact F ₁₆ CuPc ZnPc/F ₁₆ CuPc Cr 4.5 2.9×10 ^-8 8.4×10 ^-8 ohmic contact CoPc/F ₁₆ ZnPc Cr 4.5 1.1×10 ^-8 7.3×10 ^-8 ohmic contact 4T/DFH-6T Cr 4.5 9.1×10 ^-8 8.7×10 ^-7 ohmic contact ZnPc/F ₁₆ CuPc Mo 4.6 2.8×10 ^-8 9.1×10 ^-8 ohmic contact PtPc/F ₁₆ CuPc Mo 4.6 3.3×10 ^-8 1.3×10 ^-7 ohmic contact 5T/DFH-6T Mo 4.6 5.3×10 ^-7 7.7×10 ^-6 ohmic contact ZnPc/F ₁₆ CuPc Cu 4.65 5.3×10 ^-8 1.3×10 ^-7 ohmic contact H2Pc/F ₁₆ ZnPc Cu 4.65 4.1×10 ^-8 8.6×10 ^-8 ohmic contact CuPc/F ₁₆ FePc Cu 4.65 3.0×10 ^-8 7.5×10 ^-8 ohmic contact CoPc/F ₁₆ CuPc Cu 4.65 4.9×10 ^-8 1.3×10 ^-7 ohmic contact BP2T/F ₁₆ CuPc Cu 4.65 7.5×10 ^-8 3.1×10 ^-7 ohmic contact NiPc/CuPc/F ₁₆ ZnPc Cu 4.65 4.5×10 ^-8 8.1×10 ^-8 ohmic contact CoPc/ZnPc/F ₁₆ ZnPc Cu 4.65 6.2×10 ^-8 9.8×10 ^-8 ohmic contact ZnPc/F ₁₆ ZnPc/DFH-6T Cu 4.65 8.5×10 ^-7 9.4×10 ^-6 ohmic contact ZnPc/F ₁₆ CuPc Au 5.1 1.0×10 ^-7 1.1×10 ^-7 ohmic contact CuPc/F ₁₆ CuPc Au 5.1 1.2×10 ^-7 1.4×10 ^-7 ohmic contact CoPc/F ₁₆ CoPc Au 5.1 9.4×10 ^-8 1.1×10 ^-7 ohmic contact CuPc/F ₁₆ ZnPc Au 5.1 1.1×10 ^-7 1.1×10 ^-7 ohmic contact 6T/F ₁₆ CuPc Au 5.1 2.9×10 ^-7 3.1×10 ^-7 ohmic contact 6T/F ₁₆ ZnPc Au 5.1 2.8×10 ^-7 3.3×10 ^-7 ohmic contact 6T/DFH-6T Au 5.1 8.2×10 ^-7 9.2×10 ^-7 ohmic contact BP2T/F ₁₆ CuPc Au 5.1 2.2×10 ^-7 2.5×10 ^-7 ohmic contact 6T/CuPc/F ₁₆ CuPc Au 5.1 2.6×10 ^-7 3.1×10 ^-7 ohmic contact CoPc/CuPc/F ₁₆ CuPc Au 5.1 2.0×10 ^-7 2.2×10 ^-7 ohmic contact CuPc/F ₁₆ CuPc/F ₁₆ CoPc Au 5.1 2.1×10 ^-7 2.4×10 ^-7 ohmic contact ZnPc/F ₁₆ CuPc Pt 5.65 1.2×10 ^-7 1.2×10 ^-7 ohmic contact ZnPc/F ₁₆ ZnPc Pt 5.65 1.1×10 ^-7 1.1×10 ^-7 ohmic contact CoPc/F ₁₆ FePc Pt 5.65 1.0×10 ^-7 9.7×10 ^-8 ohmic contact CuPc/F ₁₆ CuPc Pt 5.65 2.1×10 ^-7 2.5×10 ^-7 ohmic contact NiPc/F ₁₆ ZnPc Pt 5.65 8.0×10 ^-8 8.1×10 ^-8 ohmic contact 6T/DFH-6T Pt 5.65 1.1×10 ^-6 1.3×10 ^-6 ohmic contact CoPc/CuPc/F ₁₆ CuPc Pt 5.65 1.4×10 ^-7 1.5×10 ^-7 ohmic contact H ₂ Pc/CuPc/F ₁₆ CuPc Pt 5.65 1.3×10 ^-7 1.4×10 ^-7 ohmic contact

Fig. 1c shows the current-voltage curves of the two device structures shown in Fig. 1a and Fig. 1b. For the device structure shown in Figure 1a, ITO is used as the electrode 2, as the anode, zinc phthalocyanine as the organic semiconductor active layer 3, zinc phthalocyanine and copper fluorophthalocyanine constitute the buffer layer 4, and the electrode 5 is a silver electrode. For the device structure shown in Figure 1b, ITO is used as the electrode 2, the organic semiconductor active layer 3 is zinc phthalocyanine, and the electrode 4 is a silver electrode as the cathode. The current increases linearly with voltage, indicating that the contacts are ohmic. In the dark state, the conductivity of the device containing the buffer layer is significantly higher than that of the device without the buffer layer. Under the condition of light, the current-voltage curve of the device containing the buffer layer almost coincides with the current-voltage curve of the dark state, indicating that it is not sensitive to light. The insensitivity to light makes it suitable for use in organic photovoltaic devices.

Example 2:

Copper phthalocyanine (CuPc) and fluorocopper phthalocyanine (F ₁₆ CuPc) used are commercial products, which are used after sublimation purification.

The device structure of an organic field effect transistor containing an electrical contact material of an organic heterojunction as a buffer layer is shown in Figure 2a. A layer of Ta metal film was coated on the 7059 glass substrate 1 by radio frequency magnetron sputtering method, the sputtering conditions were: background vacuum 2×10 ^-3 Pa, Ar gas pressure 1Pa, radio frequency power 500W, into grid 2. Continuously sputter a layer of 300nm Ta ₂ O ₅ on the gate 2 by DC magnetron sputtering method Reactive sputtering: background vacuum 2×10 ^-3 Pa, O ₂ pressure 0.9Pa, DC power 500W, as insulation Layer 3. Then adopt the molecular vapor deposition method to deposit copper phthalocyanine with a thickness of about 30 nanometers on the insulating layer 3, and the vacuum degree is 10 ^-4 Pa to form the organic semiconductor active layer 4; 2nm copper fluorinated phthalocyanine thin film forms an organic heterojunction interpenetrating network structure, the deposition method and conditions are the same as above, and a buffer layer 5 composed of an electrical contact material containing an organic heterojunction is formed; finally vacuum thermal evaporation is used 60nm Au was deposited on the buffer layer 5 and the source-drain electrodes 6 were formed using the method described above, and the vacuum during thermal evaporation was 10 ^-4 Pa.

The output characteristic curves of organic field effect transistors using electrical contact materials containing organic heterojunctions as buffer layers and transistors without buffer layers are shown in Figure 2b, where the two curves in (A) ring are devices without buffer layers, (B) The two curves inside the circle are devices with a buffer layer. At low drain voltages, the current increases linearly. When the gate-source voltage (V _G ) is 30 volts and 50 volts, comparing the two curves, it can be seen that the use of an electrical contact material containing an organic heterojunction as a buffer layer in the range of a drain-source voltage (V _D ) of 10 volts Transistors exhibit higher drain-source current (I _D ). At the same time, it can also be seen from FIG. 2b that the resistance of the transistor containing the electrical contact material of the organic heterojunction as the buffer layer is significantly reduced. The transfer characteristic curve of the corresponding organic field effect transistor device is shown in Fig. 2c, and _ID depends significantly on V _G . The electrical parameters of the organic field effect transistor device using the electrical contact material containing the organic heterojunction as the buffer layer are calculated according to the curve shown in Fig. 2c. The hole carrier mobility in the saturation region is 0.014cm ² V ^-1 s ^-1 , and the on-off current ratio is 4×10 ³ .

Example 3:

The fluorocopper phthalocyanine (F ₁₆ CuPc), zinc phthalocyanine (ZnPc) and fullerene (C ₆₀ ) used are commercial products, which are used after purification by sublimation. The conductive film ITO is used as the electrode 2 to cover the glass substrate 1, and the whole glass containing the conductive film is a commercial product.

The structure of an organic photovoltaic device containing an electrical contact material of an organic heterojunction as a buffer layer is shown in Figure 3a. All organic layers are prepared by vacuum molecular vapor deposition method, and the vacuum degree is 10 ^-5 Pa. First, a buffer layer 3 with a thickness of 4 nanometers is prepared on the ITO electrode 2. The buffer layer 3 is composed of organic semiconductor materials fluorophthalocyanine copper and phthalocyanine zinc. First, the vacuum molecular vapor deposition method is used to deposit fluorophthalocyanine copper. The temperature is 150 degrees Celsius, the thickness is 2 nanometers, and discrete crystal grains are formed, and then the zinc phthalocyanine is deposited by the same method and conditions as above, and the thickness is 2 nanometers. Together, they form an organic heterojunction interpenetrating network structure, forming a structure containing The electrical contact material of the organic heterojunction serves as the buffer layer 3 . Then, zinc phthalocyanine was deposited on the buffer layer 3 using the same method and conditions as above to form the active layer 4 of the organic semiconductor layer. The organic semiconductor active layer 5 is formed by depositing _C60 on the organic semiconductor active layer 4 using the same method and conditions as above. Finally, on the organic semiconductor active layer 5, the metal electrode aluminum is deposited by vacuum thermal evaporation to form the electrode 6, and the vacuum degree is 10 ⁻⁴ Pa.

The current-voltage curves of organic photovoltaic devices using heterojunction organic semiconductors as buffer layers and without buffer layers under dark and light conditions are shown in Figure 3b. The light conditions were simulated sunlight AM1.5, and the light intensity was 100 milliwatts per square centimeter. Under the condition of dark state and no light, the photovoltaic device with buffer layer has a small current when it is negatively biased, but the current increases sharply with the increase of voltage under forward voltage, showing good diode rectification characteristics, as shown in Figure 3b curve (c). Under light conditions, the device exhibits photovoltaic properties, see curve (d) in Figure 3b. Curves (a) and (b) in FIG. 3b are the current-voltage curves of the organic photovoltaic device without buffer layer under dark and light conditions. The performance parameters of organic photovoltaic devices with buffer layer and without buffer layer are shown in Table 2.

Table 2 contains the performance parameters of buffer layer and organic photovoltaic device without buffer layer performance parameters Without buffer layer Contains buffer layer V _oc (volt) 0.44 0.42 I _sc (milliamps per square centimeter) 1.87 2.22 FF 0.31 0.38 η(%) 0.25 0.35 R _s (ohms per square centimeter) 185 45 R _sh (ohms per square centimeter) 500 667

The present invention is not limited to the above-described embodiments. Generally speaking, the heterojunction organic semiconductor buffer layer disclosed in this patent can be used in other organic semiconductor devices, and is a device in two-dimensional and three-dimensional integrated devices. These integrated devices may be used in flexible integrated circuits, active matrix displays and photovoltaic cells. Low temperature processing can be achieved using electronic devices based on the present invention.

Claims (8)

1, a kind of contact material that contains organic heterojunction is characterized in that the described contact material that contains organic heterojunction is made up of electron type and cavity type organic semiconductor and the heterojunction that constitutes thereof.

2,, it is characterized in that described electron type and cavity type organic semiconductor belong to same analog derivative by the described contact material that contains organic heterojunction of claim 1.

3, by the described contact material that contains organic heterojunction of claim 2, it is characterized in that described P-type semiconductor layer is made of one of CuPc, phthalocyanine nickel, Phthalocyanine Zinc, phthalocyanine cobalt, phthalocyanine platinum, free base phthalocyanine or two kinds of materials respectively at least, the N-type semiconductor layer is made of one of fluoro CuPc, fluoro Phthalocyanine Zinc, fluoro FePC and fluoro phthalocyanine cobalt or two kinds of materials respectively at least.

4, by the described contact material that contains organic heterojunction of claim 2, it is characterized in that described P-type semiconductor layer is respectively by thiophene oligomers, polythiophene, two (biphenyl-4,4 ')-2, one of 2 '-two thiophene or at least two kinds of materials constitute, and the N-type semiconductor layer is made of the fluoro Uniformpoly thiophene.

5, by the described metal electrode of claim 1, it is characterized in that work content greater than 4.3 electron-volts, less than 5.7 electron-volts.

6, by the described metal electrode of claim 5, it is characterized in that a kind of or wherein two or more metal alloy among ITO, Al, Mg, Ag, Ta, Cr, Mo, Cu, Au, the Pt.

7, a kind of employing contains the organic field effect tube of the contact material of organic heterojunction as resilient coating, comprise, substrate (1), the gate electrode (2) that contacts with substrate (1), the insulated gate (3) that contacts with gate electrode (2), the organic semiconductor active layer (4) that contacts with insulated gate (3), the resilient coating that contact material constituted (5) that contains organic heterojunction that contacts with organic semiconductor active layer (4), the source/drain electrode (6) that contacts with resilient coating (5).

8, a kind of employing contains the organic film photovoltaic cell of the contact material of organic heterojunction as resilient coating, comprise, substrate (1), the transparency electrode (2) that contacts with substrate (1), the resilient coating that contact material constituted (3) that contains organic heterojunction that contacts with transparency electrode (2), the organic semiconductor active layer (4) that contacts with resilient coating (3), the organic semiconductor active layer (5) that contacts with organic semiconductor active layer (4), the metal electrode (6) that contacts with organic semiconductor active layer (5).

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